Kids Love to Crash Their Toy Cars Together

Kids love to crash their toy cars together. One such collision involves a 0.5 kg car moving at 0.3 m/s colliding with a stationary toy car of mass 0.3 kg. The two toys stick together and move away from the collision point at 0.188 m/s. What is the ratio of the initial kinetic energy of the system to the final energy of the system?

A) 0.63
B) 1.6
C) 2.5
D) 4.2
E) 1.0 The kinetic energy stays the same.)